The goals of this study are to determine whether 10 candidate genes influence susceptibility to SLE and to 2 specific disease manifestations; lupus nephritis and the antiphospholipid antibody (APLA) syndrome. The GCRC will be utilized to obtain blood samples for APLA testing, as well as serum and DNA samples for long-term storage (and future use). In addition, during the GCRC visit SLE patients and family members will complete the enrollment process including provision of buccal smear samples and questionnaire information.